"Available information suggests that a dispute over the club's leadership is the reason behind the killing," a police official said.

Police were also looking into whether any rivalry over his construction and transport business was linked to his killing, he mentioned.

The arrestees are -- Raju Hossain Raju, Rezaul Rana, Abdul Al Mamun and Altaf Hossain Alam. Raju is an accused in Meraj murder at the club in September last year and Alam is the younger brother of infamous Pichchi Hannan.

Piaru, also a senior vice-president of Bangladesh Football Federation, was killed in a hail of bullets outside the club in Dhanmondi residential area. Two policemen and an ansar commander were also injured in the incident.

Family members however ruled out business rivalry as a reason for his murder. They said Piaru was a cardiac patient and gradually withdrew himself from active involvement in business. So, there was no possibility of any dispute with him over business.

The victim's brother filed a murder case with Dhanmondi Police Station yesterday evening without accusing anybody.

Piaru's body was handed over to his family yesterday morning.

Meanwhile, different political parties including the Awami League and sports organisations yesterday condemned the killing of Piaru and demanded immediate arrest of the killers.

The other parties and organisations are Jatiya Samajtantrik Dal, Abahani Limited, Mohammedan Sporting Club, Bangladesh Cricket Board, Swadhin Bangla Football Team, Bangladesh Sports Journalists Association, Brothers Union and Bangladesh Olympic Association.